1. Field of the Invention
The present inventions relates to apparatus and methods for advancing a borehole using laser-mechanical energy. In particular the present inventions relate to such apparatus and methods for laser assisted drilling of boreholes using downhole motors as the source for rotating a laser beam and a mechanical bit. In particular, the present inventions relate to unique and novel systems for, configurations of, and methods for utilizing, a laser bottom hole assembly to advance a borehole.
2. Discussion of Related Art
The novel and innovative co-assigned inventions and teachings set forth in: (1) patent application Ser. No. 12/706,576, filed Feb. 16, 2010; and, (2) patent application Ser. No. 12/840,978 filed Jul. 21, 2010, the entire disclosures of which are incorporated herein by reference, provide, for example and in general, for the transmission of high power laser energy over great distances without substantial loss of power.
The novel and innovative co-assigned inventions and teachings set forth in: (1) patent application publication number 2010/0044106, filed Aug. 19, 2009; (2) patent application publication number 2010/0044104, filed Aug. 19, 2009; (3) patent application publication number 2010/0044105, filed Aug. 19, 2009; (4) patent application publication number 2010/0044102, filed Aug. 19, 2009; and, (5) patent application publication number 2010/0044103, filed Aug. 19, 2009, the entire disclosures of each of which are incorporated herein by reference, provide, for example and in general, for methods, systems and apparatus for laser mechanical drilling activities.
In general, and by way of historical overview, the advancement of boreholes, e.g., the drilling of oil, gas, or geothermal wells, and the apparatus for such tasks involve, among other things, the use of a drilling rig, which could be land or water based. The drilling rig advances a set of jointed tubulars, e.g., drill pipe, having a mechanical drill bit attached to the end of the drill pipe. As the drill pipe and bit are advanced toward/into the earth, the bit would be rotated against the earth's surface, or the bottom surface of the borehole, to cut, crush, scrape or otherwise remove or displace the earth through mechanical force and interaction. In this way the borehole would be advanced.
Typically, during this type of drilling the bit is forced against the bottom surface of the borehole, at times with thousands of pounds of force. During drilling the bit is rotated against the bottom of the borehole surface by rotating the drill pipe to which the bit is attached. A device on the drilling rig, such as a top drive or rotary table, in turn, rotates the drill pipe. Thus, as the borehole advances, the length of drill string increases and consequentially the distance between the drill bit and the rig increases, which results in a longer and longer drill string that must be rotated. In some wells this distance can exceed 10,000 feet. Thus, in this type of drilling the distance between the source of rotational movement, which also is referred to herein as a “rotational movement source”, and by way of example in a conventional drilling rig could be the top drive, and the drill bit can be thousands of feet, and at times tens-of-thousands of feet.
Further, the cuttings, waste material, or debris that is removed or displaced by the mechanical action of the drill bit must be carried up and out of the borehole. Typically, in this type of drilling, a drilling fluid, such as water, brine or drilling mud, is pumped into the inside of the drill string, down into and out of the bit, and up the annulus that is formed between the outside of the drill string and the inside walls of the borehole or casing. In this way the drilling fluid carries away removed or displaced material from the borehole.
The great distance between the source of rotational movement and the drill bit in the forgoing type of drilling has been problematic, to greater and lesser degrees. Although, it is believed that the forgoing type of drilling is widely practiced. To overcome the problems associated with these great distances, and to provide additional benefits, locating the rotational movement source in close proximity to the drill bit has been suggested and implemented. Thus, in these embodiments the rotational movement source is positioned at the end of a drill string, coiled tube, wireline, or other means of conveyance into a borehole, in proximity to the drill bit. In this way, the source of rotational movement is placed in the borehole, at or near the bit, and consequentially at or near the bottom of the borehole.
By way of example, one such embodiment of a downhole motor is disclosed in Clark et al. U.S. Pat. No. 3,112,801 (“Clark '801”), the entire disclosure of which is incorporated herein by reference. In general, Clark '801 provides, for example, a motor that is fashioned along the lines of what has become known as a Moineau device, which is described in the Moineau patents, e.g., U.S. Pat. Nos. 1,892,217 and 2,028,407. Moineau devices essentially have an inner and an outer member that are axially arranged with their centerlines being parallel. The outer member has internal helical threads and the inner member has external helical threads, with the outer member having one additional thread to the inner member. The outer and inner members intermesh and can function as a positive displacement motor, i.e, a source of rotational movement, if a driving fluid (liquid, gas, or foam) is forced through them, or a positive displacement pump if an external rotation force is applied to one of the members. Depending upon the specific configuration the inner member may rotate and the outer member may be fixed or the outer member may rotate and the inner member may be fixed. In Clark '801, the inner member, which Clark '801 refers to as the rotor, rotates and the outer member, which Clark '801 refers to as the stator, is stationary. As Clark '801 notes, “[t]he rotor rotates about its own axis and also orbits in a cylindrical path about the axis of the stator.” (Clark '801 column 1 lines 41-45) This orbital movement of the inner member of a Moineau device with respect to the outer member has also been referred to as nutation, gyration and nutation-gyration. Clark '801, as well as other teachings, provides various mechanical means to accommodate this orbiting motion and bring, or transmit, the rotational movement back to a non-orbiting centerline axis.
By way of example, another such embodiment of a downhole motor is disclosed in Clark U.S. Pat. No. 3,603,407 (“Clark '407”), the entire disclosure of which is incorporated herein by reference. In Clark '407 there is provided, for example, a Moineau device in which the outer member rotates and the inner member is fixed. Thus, Clark '407 refers to the outer member as an “outer gear having internal helical threads and comprising the rotor to which the drill bit is connected, the inner gear having external threads and being fixed against rotation, the arrangement being such that the inner gear is free to gyrate when driving force flows between the gears so that the outer gear member and the attached drill bit will rotate in a concentric path.” (Clark '407 Abstract) This configuration where the outer member rotates and the inner member is fixed has been referred to as a “reverse Moineau” device, motor or pump, or as an “inverted Moineau” device, motor or pump.
A further example of a reverse Moineau motor is provided in Tiraspolsky et al. U.S. Pat. No. 4,011,917 (“Tiraspolsky”), the entire disclosure of which is incorporated herein by reference. Tiraspolsky, for example, provides for the inner non-rotating member of the Moineau device to have a channel through it. An additional example of a reverse Moineau motor having a channel in the non-rotating member is found in Oglesby U.S. Pat. No. 7,055,629 (“Oglesby”).
Although a passing reference is made in Oglesby to “using laser . . . energies applied to the materials to be ‘drilled’ . . . ” (see generally, Oglesby column 4 line 53 to column 5 line 2), none of the forgoing references teach or suggest the systems, components, configurations or methods, that are provided by the present inventions for a laser bottom hole assembly and methods of drilling therewith.